Damages of 20,000 have been awarded to a convicted sex offender who sued Facebook, the operator of a page called Keeping our Kids Safe from Predators 2.
Facebook Ireland Limited, hosted the page, operated by Joseph McCloskey.
The High Court in Belfast said the information published by Mr McCloskey "harmed the public interest, creating a risk of reoffending".
The plaintiff, CG, was convicted in 2007 of a number of sex offences.
He was sentenced to 10 years imprisonment and released on licence in 2012.
CG brought an action seeking damages and an injunction on the basis that Facebook and Mr McCloskey misused private information, are in breach of Articles 2, 3 and 8 of the European Court of Human Rights, and are guilty of actionable negligence.
He also sued Facebook over separate postings by the father of one of his victims.
The judge found that Mr McCloskey was liable to CG for misuse of private information and for unlawful harassment.
The judge also made an injunction against Mr McCloskey preventing him from harassing, pestering, annoying or molesting CG whether by publishing, distributing, broadcasting or transmitting any information on Facebook or otherwise.
He also ordered Facebook to close the profile/page Keeping our Kids Safe from Predators 2.
The judge awarded CG damages of 20,000.
This relates to 15,000 against Facebook and Mr McCloskey in respect of the postings by Mr McCloskey.
The judge also awarded 5,000 against Facebook over the postings by the father of one of CG's victims, who operated a separate page.
Lawyers for the sex offender who issued proceedings have predicted it could pave the way for compensation claims by many others who feel similarly aggrieved.